EP0598342A1 - Magnetoresistiver Sensorkopf mit zwei Elementen - Google Patents

Magnetoresistiver Sensorkopf mit zwei Elementen Download PDF

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Publication number
EP0598342A1
EP0598342A1 EP93118291A EP93118291A EP0598342A1 EP 0598342 A1 EP0598342 A1 EP 0598342A1 EP 93118291 A EP93118291 A EP 93118291A EP 93118291 A EP93118291 A EP 93118291A EP 0598342 A1 EP0598342 A1 EP 0598342A1
Authority
EP
European Patent Office
Prior art keywords
head
sensing head
elements
thin films
magnetoresistive
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP93118291A
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English (en)
French (fr)
Other versions
EP0598342B1 (de
Inventor
Daniel A. Nepela
Erich P. Valstyn
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Read Rite Corp
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Read Rite Corp
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Filing date
Publication date
Application filed by Read Rite Corp filed Critical Read Rite Corp
Publication of EP0598342A1 publication Critical patent/EP0598342A1/de
Application granted granted Critical
Publication of EP0598342B1 publication Critical patent/EP0598342B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
    • G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
    • G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
    • G11B5/3906—Details related to the use of magnetic thin film layers or to their effects
    • G11B5/3945—Heads comprising more than one sensitive element
    • G11B5/3948—Heads comprising more than one sensitive element the sensitive elements being active read-out elements
    • G11B5/3951—Heads comprising more than one sensitive element the sensitive elements being active read-out elements the active elements being arranged on several parallel planes
    • G11B5/3954—Heads comprising more than one sensitive element the sensitive elements being active read-out elements the active elements being arranged on several parallel planes the active elements transducing on a single track
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
    • G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
    • G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
    • G11B5/3967—Composite structural arrangements of transducers, e.g. inductive write and magnetoresistive read

Definitions

  • Inductive write heads are used for recording information on magnetic media, such as magnetic disks.
  • the recorded information can be read out by an inductive read/write head.
  • MR heads can be used for sensing signals which have been recorded on a magnetic medium.
  • the signal sensed by an MR head is proportional to the magnetic flux associated with the recorded signal, and not to the rate of change of flux which is sensed by an inductive head.
  • an MR head can detect a magnetic field representing a recorded signal without any relative motion between the storage medium and the MR head.
  • a typical thin film MR head incorporates a single MR element, preferably made of a layer of Permalloy having an easy axis of magnetization.
  • a data storage apparatus such as a disk drive
  • an electric sense current is directed to the MR element.
  • the magnetic field being sensed exerts a torque on the magnetic moment in the MR thin film causing a change in the resistivity of the film.
  • the change in resistivity is proportional to the strength of the field being measured and causes variations in the resistance of the MR element. Detection of such variations provides a readout signal related to the data signal recorded on the magnetic medium.
  • Distortion of the readout signal results when the remanent magnetic moment M r t of the medium or disk is high. Then the MR head periodically saturates, so that the magnetization remains fixed in orientation despite a further increase in the strength of the applied field. In such event, undesirable odd harmonics are produced. Even harmonics are generated as a result of nonlinear variations in the magnetoresistance of the MR head. The even and odd harmonics appear as distortions in the signal being read out.
  • a small M r t avoids saturation effects and ensures operation in the linear range of the ⁇ / ⁇ curve, where p is the resistivity, but also results in a lower signal.
  • a higher signal can be achieved by increasing the sense current.
  • the sense current applied to each MR element is limited due to the fact that the sense current in one element is the bias current for the other element.
  • the current must be of such a magnitude, typically 3-5 milli-amperes, that the operating point (OP) of each element is in the center of the linear range of the ⁇ p/p curve.
  • An object of this invention is to provide an MR head assembly that achieves a significant increase in level of the readout signal.
  • Another object of this invention is to provide an MR head assembly which avoids the limitation on sense current and realizes a significant increase in output signal amplitude.
  • Another object is to provide an MR head assembly that allows the use of a magnetic medium or disk having a relatively lower remanent moment (Mrt).
  • a further object is to provide an MR head assembly that reduces the requirement for close matching of the magnetic properties and thicknesses of MR sensing elements.
  • a read/write head structure incorporates an MR sensing head and an inductive write head that is superimposed on the MR head structure.
  • the inductive write head is conventional and formed with thin film magnetic layers of Permalloy in a well known manner.
  • the present disclosure is directed to the novel MR head, which is part of the overall read/write head structure.
  • the MR head of this invention comprises two MR elements or MR layers and two antiferromagnetic (AFe) elements or layers.
  • the MR elements are made of soft Permalloy and the AFe elements are made from an iron manganese alloy (FeMn), for example.
  • FeMn iron manganese alloy
  • Each AFe element is formed adjacent to and is in intimate atomic contact with a respective MR element.
  • Each AFe element is coupled by exchange interaction at room temperature to the MR element and serves as a biasing device.
  • an exchange field He is applied in a direction perpendicular to the surface of the disk.
  • the current through a first MR/AFe structure provides a magnetic field to the opposing second MR/AFe structure. This magnetic field is in a direction that is opposite to the exchange field existing at the second MR/AFe structure.
  • a dual element MR head assembly includes a first MR layer 10 and a second MR layer 12 which are substantially parallel with preferably an insulating oxide layer 18 therebetween.
  • the MR layers 10 and 12 are preferably made of thin films of soft magnetic material having a ⁇ / ⁇ equal to or greater than 1 %, each having approximately the same thickness in the range of 100-500 Angstroms, for example.
  • thin film layers 14 and 16 of antiferromagnetic (AFe) material such as iron manganese (FeMn) are deposited, by sputtering for example, respectively on the MR layers 10 and 12 and coextensively with the MR layers.
  • a DC field is applied in the desired direction of the exchange field during the sputtering of the first FeMn layer 14 onto the MR layer 10.
  • a DC field is applied in an opposite direction during the sputtering of the second FeMn layer 16 onto the MR layer 12.
  • Each of the FeMn layers 14 and 16 is about 100-300 Angstroms thick.
  • the thin FeMn material locks onto the Permalloy material of the MR layers 10 and 12.
  • the FeMn layers are coupled by exchange interaction to the MR layers 10 and 12 and serve as biasing devices.
  • the head assembly is shielded by soft magnetic Permalloy shields 20 and 22.
  • the Permalloy shields 20 and 22 are preferably made of a composition of 81% nickel and 19% iron and each shield is about 1.5 to 4.0 microns thick.
  • the head assembly and shields are deposited on and supported by a substrate (shown in Fig. 4), which may be made of a nonmagnetic ceramic material.
  • a proper exchange bias is provided by passing a current through the magnetostatically coupled pair of MR elements and their associated FeMn antiferromagnetic layers during cooling of the MR/AFe structure, while the assembly of the MR structure and superimposed inductive write head (not shown) is cooled to room temperature after hard baking of the photoresist of the superimposed inductive write head.
  • the Permalloy elements of the pair of MR structures are saturated in opposite directions and the antiferromagnetic layers are oriented by exchange coupling in the desired directions as the layers become progressively more antiferromagnetic while cooling. In this way, the head structure is initialized.
  • bias current is directed to a conductor 34 (Fig. 2) and the current is split and applied substantially equally to MR elements 10 and 12.
  • a magnetic field H is produced at each MR sensor 10 and 12 by the application of sense current to the conductor pairs 24 and 26.
  • the magnetic field H derived from the applied sense current at each sensor biases the other sensor.
  • the current-derived fields that are applied symmetrically and in opposite directions to the sensors overcome the exchange field in each sensor to place both sensors at the operating point (Fig. 3). With this sensor assembly, larger sense currents and thus higher signals are obtained.
  • the applied sense current is about 2-4 times greater, say about 10-40 milli-amperes, than that which is used with conventional prior art dual MR heads.
  • the applied current produces a magnetic field H ; at each sensor 10 and 12.
  • the magnetic field H overcomes the exchange field He which is provided by the exchange layers 14 and 16 and applied symmetrically but in opposite directions to the sensors, as illustrated in Fig. 1.
  • the exchange field He which measures in the range of 5-20 Oersteds, is applied in a direction that is perpendicular to the surface of the magnetic medium or magnetic disk. Antiferromagnetic elements with larger exchange fields can be accommodated by a change in the angle of the exchange field from 90 relative to the disk surface to a smaller angle.
  • the dual element MR head with MR layers 10 and 12 senses the recorded signal differentially and the differential signal is fed through leads 28 and 30 to a differential amplifier 32.
  • the differential signal provides common mode rejection of noise from electrical and thermal effects and minimizes harmonic distortion.
  • a higher signal output can be obtained with an increase in signal-to-noise ratio.
  • a magnetic medium having a lower Mrt can be used with a resultant increase in signal resolution.
  • the magnetization curve is symmetrical relative to the ⁇ p/p axis.
  • the specifications for matching the thicknesses and magnetic properties of the two MR elements are less restrictive because the location of the operating points on the ⁇ p/p curve is less critical.
  • the combined inductive write head/dual element MR read head has the advantages of increased signal output without limitation on the sense current and improved signal-to-noise ratio. The requirement for close matching of the two MR elements is minimized.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Magnetic Heads (AREA)
  • Recording Or Reproducing By Magnetic Means (AREA)
  • Measuring Magnetic Variables (AREA)
  • Hall/Mr Elements (AREA)
EP93118291A 1992-11-16 1993-11-11 Magnetoresistiver Sensorkopf mit zwei Elementen Expired - Lifetime EP0598342B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US976536 1992-11-16
US07/976,536 US5309305A (en) 1992-11-16 1992-11-16 Dual element magnetoresistive sensing head

Publications (2)

Publication Number Publication Date
EP0598342A1 true EP0598342A1 (de) 1994-05-25
EP0598342B1 EP0598342B1 (de) 1998-05-27

Family

ID=25524200

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93118291A Expired - Lifetime EP0598342B1 (de) 1992-11-16 1993-11-11 Magnetoresistiver Sensorkopf mit zwei Elementen

Country Status (7)

Country Link
US (1) US5309305A (de)
EP (1) EP0598342B1 (de)
JP (1) JPH06215334A (de)
KR (1) KR940012244A (de)
CN (1) CN1087194A (de)
DE (1) DE69318804T2 (de)
TW (1) TW305995B (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0691642A3 (de) * 1994-06-13 1997-01-02 Sony Corp Magneto-resistiver Magnetkopf

Families Citing this family (45)

* Cited by examiner, † Cited by third party
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US5444589A (en) * 1993-12-02 1995-08-22 International Business Machines Corporation Rotary actuator disk drive with identical dual-element read/write transducers
US5696654A (en) * 1994-04-21 1997-12-09 International Business Machines Corporation Dual element magnetoresistive sensor with antiparallel magnetization directions for magnetic state stability
JP2963003B2 (ja) * 1994-05-02 1999-10-12 三洋電機株式会社 軟磁性合金薄膜及びその製造方法
US6038106A (en) * 1995-05-10 2000-03-14 International Business Machines Corporation Piggyback magneto-resistive read/write tape head with optimized process for same gap read/write
US5680280A (en) * 1995-09-11 1997-10-21 Texas Instruments Incorporated Magnetic field sensor using heterojunction bipolar transistors
US5703485A (en) * 1996-07-29 1997-12-30 Headway Technologies, Inc. Method and test structure for determining magnetic domain switching field when fabricating patterned exchange biased magnetoresistive (MR) head
US5684658A (en) * 1996-10-07 1997-11-04 Headway Technologies, Inc. High track density dual stripe magnetoresistive (DSMR) head
US5721008A (en) * 1996-10-15 1998-02-24 Seagate Technology, Inc. Method for controlling sensor-to-sensor alignment and material properties in a dual magnetoresistive sensor
US5766780A (en) * 1996-10-15 1998-06-16 Seagate Technology, Inc. Reversed order NIMN exchange biasing for dual magnetoresistive heads
US5783460A (en) * 1996-10-25 1998-07-21 Headway Technologies, Inc. Method of making self-aligned dual stripe magnetoresistive (DRMR) head for high density recording
US5706151A (en) * 1996-12-12 1998-01-06 Eastman Kodak Company Low bias current paired magnetoresistive head with misaligned anisotropy axes
WO1999059145A1 (en) * 1998-05-13 1999-11-18 Storage Technology Corporation Method for reading both high and low density signals with an mr head
JP2000003501A (ja) * 1998-06-12 2000-01-07 Sony Corp 磁気信号再生装置及び磁気信号再生方法
US6278594B1 (en) 1998-10-13 2001-08-21 Storage Technology Corporation Dual element magnetoresistive read head with integral element stabilization
US6230390B1 (en) * 1998-10-30 2001-05-15 Headway Technologies, Inc. Canted longitudinal patterned exchange biased dual-stripe magnetoresistive (DSMR) sensor element and method for fabrication thereof
US6191925B1 (en) 1999-06-18 2001-02-20 Storage Technology Corporation Dual element read with shaped elements
US6291087B1 (en) 1999-06-21 2001-09-18 Headway Technologies, Inc. Magnetoresistive (MR) sensor element with enhanced resistivity sensitivity and enhanced magnetic exchange bias
JP3206810B2 (ja) * 1999-09-02 2001-09-10 マイクロマグネ有限会社 磁気検出装置
US7227726B1 (en) 2002-11-12 2007-06-05 Storage Technology Corporation Method and system for providing a dual-stripe magnetoresistive element having periodic structure stabilization
JP3729498B2 (ja) * 2003-02-26 2005-12-21 株式会社東芝 磁気抵抗効果ヘッドおよび磁気記録再生装置
US8139301B1 (en) 2009-07-22 2012-03-20 Western Digital (Fremont), Llc Disk drive comprising a dual read element and delay circuitry to improve read signal
US9431039B1 (en) 2013-05-21 2016-08-30 Western Digital (Fremont), Llc Multiple sensor array usable in two-dimensional magnetic recording
US8891207B1 (en) 2013-06-07 2014-11-18 Western Digital (Fremont), Llc Connection schemes for a multiple sensor array usable in two-dimensional magnetic recording
US8908333B1 (en) 2013-08-13 2014-12-09 Western Digital (Fremont), Llc Shield designed for middle shields in a multiple sensor array
US9431032B1 (en) 2013-08-14 2016-08-30 Western Digital (Fremont), Llc Electrical connection arrangement for a multiple sensor array usable in two-dimensional magnetic recording
US9135935B1 (en) 2013-10-11 2015-09-15 Western Digital Technologies, Inc. Customized head gimbal assembly bonding skew angle for adjusting two-dimensional magnetic recording reader alignment
US9042058B1 (en) 2013-10-17 2015-05-26 Western Digital Technologies, Inc. Shield designed for middle shields in a multiple sensor array
US8953284B1 (en) 2013-11-20 2015-02-10 HGST Netherlands B.V. Multi-read sensor having a narrow read gap structure
US9257145B1 (en) 2013-11-27 2016-02-09 Western Digital Technologies, Inc. Disk drive measuring down-track spacing of read sensors
US8988812B1 (en) 2013-11-27 2015-03-24 Western Digital (Fremont), Llc Multi-sensor array configuration for a two-dimensional magnetic recording (TDMR) operation
US9230578B2 (en) 2013-12-23 2016-01-05 HGST Netherlands B.V. Multiple readers for high resolution and SNR for high areal density application
US8970988B1 (en) 2013-12-31 2015-03-03 Western Digital (Fremont), Llc Electric gaps and method for making electric gaps for multiple sensor arrays
US9082435B1 (en) 2014-01-15 2015-07-14 HGST Netherlands, B.V. Fabrication of multiple sensor layers with self-aligned back edge
US9082436B1 (en) 2014-02-05 2015-07-14 HGST Netherlands B.V. Zig-zag MIMO head reducing space between three sensors
US9741369B2 (en) 2014-02-28 2017-08-22 Western Digital Technologies, Inc. Multi-track reader for improved signal to noise ratio
US9070406B1 (en) 2014-03-10 2015-06-30 Western Digital Technologies, Inc. Disk drive configuring one-dimensional and two-dimensional recording areas based on read element spacing
US9245556B2 (en) 2014-03-10 2016-01-26 Western Digital Technologies, Inc. Disk drive employing multiple read elements to increase radial band for two-dimensional magnetic recording
JP6309796B2 (ja) 2014-03-20 2018-04-11 株式会社東芝 磁気ヘッド、磁気記録再生装置、および磁気ヘッドの製造方法
US9373344B2 (en) 2014-04-16 2016-06-21 HGST Netherlands B.V. Two side by side MIMO read sensors fabricated by self-aligned processing
JP6121943B2 (ja) 2014-05-16 2017-04-26 株式会社東芝 磁気ヘッドおよび磁気記録再生装置
US9053727B1 (en) 2014-06-02 2015-06-09 Western Digital Technologies, Inc. Disk drive opening spiral crossing window based on DC and AC spiral track error
US9013824B1 (en) 2014-06-04 2015-04-21 Western Digital Technologies, Inc. Data storage device comprising dual read sensors and dual servo channels to improve servo demodulation
US9087527B1 (en) 2014-10-28 2015-07-21 Western Digital (Fremont), Llc Apparatus and method for middle shield connection in magnetic recording transducers
US9786301B1 (en) 2014-12-02 2017-10-10 Western Digital (Fremont), Llc Apparatuses and methods for providing thin shields in a multiple sensor array
US9542962B2 (en) 2015-01-23 2017-01-10 HGST Netherlands B.V. Multi-sensor reader structure having a current path with increased size to reduce noise

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EP0279537A2 (de) * 1987-02-17 1988-08-24 Seagate Technology International Magnetoresistiver Sensor und Verfahren zu seiner Herstellung
EP0325365A2 (de) * 1988-01-19 1989-07-26 Hewlett-Packard Company Kompensierter Magneto-Widerstandslesekopf
EP0406060A1 (de) * 1989-06-27 1991-01-02 Thomson-Csf Magnetwiderstandseffektwandler

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US5084794A (en) * 1990-03-29 1992-01-28 Eastman Kodak Company Shorted dual element magnetoresistive reproduce head exhibiting high density signal amplification
US5132859A (en) * 1990-08-23 1992-07-21 International Business Machines Corporation Thin film structures for magnetic recording heads

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0279537A2 (de) * 1987-02-17 1988-08-24 Seagate Technology International Magnetoresistiver Sensor und Verfahren zu seiner Herstellung
EP0325365A2 (de) * 1988-01-19 1989-07-26 Hewlett-Packard Company Kompensierter Magneto-Widerstandslesekopf
EP0406060A1 (de) * 1989-06-27 1991-01-02 Thomson-Csf Magnetwiderstandseffektwandler

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0691642A3 (de) * 1994-06-13 1997-01-02 Sony Corp Magneto-resistiver Magnetkopf
US5661620A (en) * 1994-06-13 1997-08-26 Sony Corporation Magneto-resistance effect magnetic head
US5786965A (en) * 1994-06-13 1998-07-28 Sony Corporation Magneto-resistance effect magnetic head

Also Published As

Publication number Publication date
CN1087194A (zh) 1994-05-25
KR940012244A (ko) 1994-06-23
JPH06215334A (ja) 1994-08-05
US5309305A (en) 1994-05-03
TW305995B (de) 1997-05-21
DE69318804D1 (de) 1998-07-02
EP0598342B1 (de) 1998-05-27
DE69318804T2 (de) 1998-09-24

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